1. Field of the Invention
The present invention relates to a rotary compressor in which a rotary sleeve is floatingly suspended in the central housing and a rotor with a vane is rotatably housed within said rotary sleeve. More specifically, the present invention is directed to the floating-suspension mechanism of the rotary sleeve.
2. Description of the Prior Art
Generally speaking, the vane-type rotary compressor is required to have a different performance depending on the intended use. For instance, an auto-engine supercharger is required to withstand high pressure and a wide range of rpms.
For this purpose it is effective to provide between the central housing and the vaned rotor, a rotary sleeve floatingly suspended relative to said central housing through a pneumatic bearing chamber, and to minimize the friction between the vane and the rotary sleeve by making the rotary sleeve rotate together with said rotor. Such an arrangement suppresses heat generation due to the rotational friction of the vane, realizing a non-lubricated rotation and large flow rate in a wide range of rpms.
In the above rotary compressor, whose rotary sleeve is floatingly suspended within the central housing, for the sake of smooth rotation, the rotary sleeve must maintain rotation without any deviation in the radial and axial directions and without contacting the central housing or the side housing. In other words the rotary sleeve must rotate at a specific position within the central housing and it should not be displaced so as to touch the inside surface of the central housing or the front or rear housing on both sides thereof and to cause wear or seizure.
The rotary sleeve is liable to be thermally deformed into a hourglass shape on account of its inside being heated by an adiabatically compressed gas, resulting in contact of both of its ends with the central housing.
Moreover, since the load acting on the rotary sleeve tends to be large at the center and progressively small toward the ends, it may happen that both ends of the rotary sleeve displace and come into contact with the central housing. Even under such contact, however, the rotary sleeve should be prevented from being excessively worn or being seized with the central housing.